From the past, an optical measurement method that uses flow cytometry (flow cytometer) has been used for analyzing biologically-relevant micro-particles such as cells, microorganisms, and liposomes. A flow cytometer is an apparatus that irradiates light onto micro-particles flowing through a flow channel formed in a flow cell, a microchip, and the like and detects and analyzes fluorescence and scattered light emitted from the individual micro-particles.
Some flow cytometers include a function of sorting and recovering only micro-particles having a specific property based on an analysis result, and a micro-particle apparatus that sorts cells in particular is called “cell sorter”. In such a cell sorter, in general, a flow cell or a microchip is vibrated by a vibration device or the like to form droplets of a fluid discharged from the flow channel (see Patent Documents 1 and 2).
After the droplets separated from the fluid is imparted with charges of plus (+) and minus (−), a traveling direction thereof is changed by a deflection plate or the like so that the droplets are recovered in a predetermined vessel or the like. Further, from the past, there has also been proposed a technique of distributing particular cells one by one to each reaction site of a base material used in a PCR (Polymerase Chain Reaction) method or the like using a sorting function of a cell sorter (see Patent Document 3).
Patent Document 1: Japanese Patent Translation Publication No. 2007-532874
Patent Document 2: Japanese Patent Application Laid-open No. 2010-190680
Patent Document 3: Japanese Patent Translation Publication No. 2010-510782